BY : BRUCE ROLFSEN For defensenews

With a price tag of $130 million per F-22A Raptor $330 million including research and development costs critics wonder why millions more will have to be spent to fix corrosion problems and design flaws on some of the 104 stealth fighters delivered so far by manufacturer Lockheed Martin.
Leaky fuselage access panels at the top of the jet are leading to corrosion issues in many planes. Also, problems with its core structure particularly the forward boom, which supports the plane’s weight and must endure the stresses of high-G maneuvers must be fixed.
These are among the latest in a series of problems for the Raptor as it moves from developmental test jet to operational fighter. Another problem, overheating avionics, was fixed in the last year.
An additional 79 F-22As will be added to the U.S. Air Force fleet over the next few years, bringing the total number to 183. On Oct. 31, the Air Force stood up a second operational F-22 squadron at Elmendorf Air Force Base, Alaska, the fourth overall.
None of the latest structural or avionics issues has grounded the fleet, said Brig. Gen. C.D. Moore, who oversees F-22 upgrade and sustainment across the Air Force as commander of the 478th Aeronautical Systems Wing at Wright-Patterson Air Force Base, Ohio. He logged about 100 hours as a Raptor test pilot before taking the Materiel Command desk assignment.
Despite the problems, Moore said the most recent F-22 appraisal by the Air Force Operational Test and Evaluation Center rated the jet as “suitable” for maintenance in real-world situations. In other words, most problems can, as a matter of course, be fixed by local base maintenance squadrons, and the fighter is not breaking down regularly.
Moore said he expects that as Raptors get more flight hours and are flown day to day on a wider range of missions, unexpected problems will arise — what he calls “known unknowns.” But he continues to think the service made the right calculation in having the Raptor ready for combat, rather than waiting for the jet to be perfected.
Philip Coyle, a former director of the Defense Department’s Operational Test and Evaluation Office, points out that the Air Force has spent two decades trying to get the F-22A right and meet the high expectations set for the fighter. The dilemma is not a lack of time to find and fix problems.
“What you see now is poor design and reliability,” said Coyle, now a senior adviser at the Center for Defense Information, a Washington think tank that is often critical of how defense projects are managed.
Quality assurance is also an issue. A potential metal-fatigue problem in the front of the jet’s fuselage should have been caught before 91 aircraft were built, he said.
Coyle worries that the F-22A problems are being repeated with the F-35 Lightning II, which is intended to replace the F-16 and A-10 as well as Navy and Marine Corps fighters. Though a test version of the F-35 has been grounded for several months, the jet’s builder, Lockheed Martin, is seeking Pentagon permission to fly fewer test hours.
Cutting test flights “is always a sign that the aircraft is in trouble,” Coyle said.
Fixing the Problems
The four largest aluminum access panels will be replaced with titanium panels much less susceptible to corrosion, Moore said. Each set of new panels will cost about $50,000.
In addition to the leaking access panels, there have been concerns about the aircraft’s core structure.
A year ago, Air Force Times, a Defense News sister publication, reported that F-22A structural problems could cost $1 billion to fix. But after further tests, the Air Force now estimates the fixes will be in the millions, although a final estimate for labor and parts has not yet been calculated, Moore said.
The biggest concern is the jet’s “forward boom,” which Moore compared to a backbone, supporting the weight of the plane. The Air Force learned that the titanium used in the forward boom of 91 jets had not been heat-treated and strengthened to service specifications.
Later tests concluded that the titanium in the forward boom is strong enough for the jet to meet its requirement of 8,000 flying hours, Moore said.
The Raptor had a different problem with the aft boom. Engineers were worried that the rear section of the jet, as designed, could not meet the 8,000-hour requirement, so they designed an aluminum reinforcement, called a “doubler.” That was added to the production line, but repairs to 41 earlier jets will have to be made at either the Ogden Air Logistics Center at Hill Air Force Base, Utah, or at Lockheed’s Palmdale, Calif., plant. Moore could not estimate the repair bill other than to say labor costs would be higher than the cost of the parts.
The repair depots also are replacing on 60 jets some lugs that help attach the Raptor’s wings to the fuselage. Again, the concern was that the lugs could not withstand the strain over the Raptor’s life span